Control system for room reservation

ABSTRACT

This disclosure relates to a system which displays the availability of categories of items over a predetermined number of units of time. Provision is made to constantly update the display by incrementing or decrementing the appropriate item categories between initial and final dates of use of any item. The units of time may be classified into groups to allow an expired group of units of time to be annexed to the last group of units of time to continuously utilize the system over a predetermined future time period.

O Unlted States Patent [151 3,656,113 Lince [451 Apr. 11, 1972 [54]CONTROL SYSTEM FOR ROOM 2,737,342 3/1956 Nelson", ..340/153 RESERVATION2,883,106 4/1959 Cornwell ..340/153 x [721 William Hm, mouth PM, M323323 2/1321 XSIXSITTZIII: ......::::'.5z37 [73] Assignee: UMCElectronics Company, North Haven, 3,416,133 12/1968 Hunkins..........340/334 X Conn. 3,462,739 8/1969 Scantlin ..340/151 X [22] Flled:1968 Primary Examiner-Harold I. Pitts [21] Appl. No.: 772,673Att0rney-Delio & Montgomery I 52 us. Cl ..340/153, 340/151,340/334, [571ABSTRACT 340/339 This disclosure relates to a system which displays theavaila- [51 [13. Cl. of categm'ies of items over a predetermined numberof [58] Field of Search ..340/ 153, 151, 334, 339 units f time.provision is made to constantly update the play by incrementing ordecrementing the appropriate item [56] References Clled categoriesbetween initial and final dates of use of any item. UNITED STATESPATENTS The units of time may classified into groups to allow an explredgroup of units of time to be annexed to the last group of 2,594,960 4/1952 May -340/153 x units of time to continuously utilize the systemover a 2,61 1,813 Sharpless l predetermined future time period 2,622,14212/1952 Jackel ..340/153 1 2,645,764 7/1953 McWhirter ..340/ 153 18Claims, 13 DrawingFigures I 70 com) cam: 3 2: 1, 1 7 PUNCH REHDERDLSPLHY CQUNT N eToRaeE IZ \NDlCHTORS FIND FEED CLFlSSlFlCRTION 20OCCUPHNCYI 5 DHYS SELECTOR HRRIVHL Dare 1 I FINHL OCCUPHNCY DHTE /8 If)MONTH SELECTOR MONTH mmcnroR PATENTEDAPR 1 1 1912 sum u or 9 win Q .mwum

3 Q Q] Q Q c, Q Q Q Q Q Q m5 mmum Mi Q Q Q Q 0 Q Q Q Q $2 F 1 1 1 1 1 r1 1 1 y 1 Qi Q Q Q Q Q Q Q Q Q :g

Q: QSMQ UR Q Q Q Q 4 Q Q Q c Q Q Q $3 NE @Sm Q Q Q Q Q Q Q Q Q Q 1 l I 11 I l l @N l l :5 max 6% Q Q Q Q Q Q Q Q Q Q Q Ham 4 1 1. I 1 1 1 1 Hi3: 13 T QN ED QNJZO $1 2m QL ZQ ML ZQU QLQH W Y Y mEwQQ :QQZAHP'A'TENTEDAPR 1 1 I972 SHEET 5 OF 9 DHYS ODD Mom H DHYS I045 I EVENMONTH DRY INVENTOR U8 BY wflham G Lmca CONTROL SYSTEM FOR ROOMRESERVATION This invention relates to information storage and displaysystems, and more particularly relates to systems for storing anddisplaying an inventory of different items taking into consideration thetotal availability of items, category of items, units of time over whichthe items are utilized and continuous monitoring of items placed in andremoved from availability over the time period.

A system embodying the present invention may find many applicationswhere a large number of items are continuously taken from and returnedto an inventory over predetermined units of time. It is particularlyadaptable for use in hotels, motels, hospitals, and where informationregarding the use and availability of units over successive units oftime is critical to the efficient operation. Accordingly, the inventionwill be disclosed in such environment.

At the present time, most large hotels, motels, hospitals, and the like,rely on a paper marking inventory system which is continuouslymaintained and updated by a reservation clerk. In such bookkeeping orinventory systems, mistakes and overbookings for units are frequent. Theresult may be that a reserve customer is turned away or referred toanother establishment resulting in a loss of good will. Alternatively,the establishment, to maintain good will, may give the customer a higherpriced unit at the lower reserve rate to maintain its reputation in goodwill. In either event, or analogous situation, the establishment suffersa loss of good will and/or income. Additionally, much clerical time isrequired at allpresently known reservation systems.

The present invention as applied to a hotel reservation system presentsa continuous display of all categories of rooms available for apredetermined number of days, months or other periods of time. Theinvention further provides a means for'almost instantaneously validatingreservations and recording cancellations or reservations for any numberof units within the predetermined time. The present invention furtherprovides a means for gathering statistical data regarding reservedarrival time, no-shows, walk-ins, peak periods, etc. A system embodyingthe present invention further saves much clerical, bookkeeping andreservation time and allows the reservation and reception personnel anever present, positive indication of all available units for a givennumber of units.

An object of this invention is to provide a new and improved inventoryinformation storage and display system.

Another object of this invention is to provide a new and improved systemfor maintaining and displaying-a continuous inventory of available unitsover a predetermined period of time, and further allowing immediateupdating of such inventory upon any change in reserved unit,cancellations, etc.

Another object of this invention is to provide a new and improved systemwhich will continuously display categories of available items over apredetermined number of units of time and which may be immediatelyupdatedwhen items are added to or subtracted from availability.

Another object of this invention is to provide a new and improved systemof the type described in which the units of time are divided into groupsand each group may be utilized to indicate a new period of time uponpassage of a first period of time.

Another object of this invention is to provide a new and improved systemof the type described in which the date of first use and date of finaluse of a category of items are selected and all units of timetherebetween are incrementedor decremented by the number of itemsremoved from or added to availability.

A further object of this invention is to provide a new and improvedarrangement for providing a plurality of pulse counts corresponding innumber to a number held in a storage register indicating a number ofitems to be placed in or removed ,from availability. I

The features of the invention which are believed to be novel areparticularly pointed out and definitely claimed in the concludingportion of the specification. The invention, however,

both as to its organization and operation, together with further objectsand advantages thereof, may best be appreciated by reference to thefollowing detailed description taken in conjunction with the drawings,wherein:

FIG. 1 is a block diagram of a system embodying the invention;

FIG. 2 is an illustration of a record medium in the form of a punch cardfor reading information into the system of FIG. 1;

FIG. 3 illustrates a display console;

FIG. 4 is a drawing partly in schematic and partly in block form of acircuit for reading the information on the cards of FIG. 2;

FIG. 5 is a diagram partly schematic and partly in block form of theroom category register of FIG. 1;

FIG. 6 is a diagram partly schematic and partly in block form of theclassification register of FIG. 1;

FIG. 7 is a diagram partly schematic and partly in block form of aportion of the display console of FIG. 3;

FIG. 8 is a drawing partly schematic and partly in block form of theactuating mechanism of each display register;

FIG. 9 is a diagram partly schematic and partly in block formof thearrival date register of FIG. 1 and further showing the month selectorand indicator of FIG. 1;

FIG. 10 is a diagram in block form of the final occupancy day registerof FIG. 1;

FIG. 11 is a diagram partly schematic and partly in block form of theoccupancy days selector of FIG. 1;

FIG. 12 is a diagram partly schematic and partly in block form of aregister for storing a number of units to be utilized; and

FIG. 13 is a schematic diagram of the count control and feed register ofFIG. 1.

Referring now to the drawings and, specifically, to FIGS. 1 and 2. Asystem embodying the invention includes an information or data input inthe form of a card reader 10. Card reader 10 is adapted to readinformation which is stored in a record medium which is preferably acard 11.

With specific reference to a hotel or motel, when a reservation isreceived, the necessary data is punched in the appropriate places on thecard 11 utilizing a card punch unit 12. The card 1 1 is a standard punchcard having a given number of columns (vertical) and rows (horizontal).The card is insertedinto cardreader 10 which in a conventional mannersenses the perforations in each column of the card and forwards thissensed information to appropriate storage or information handlingdevices. Considering both the system of FIG. 1 and the card of FIG. 2,the first classification on the card may be marked with the identifyingcode number of the hotel for later reference in statistical analysis.The next classifica tion on the card is the date a reservation (orcancellation) is received. The next classification on the card will showthe type or category of room selected. This information will appear incolumn, nine of the card and will be: conveyed to a room categorystorage unit l3. As will hereinafter be more specifically set forth, anynumber of room categories up to ten may be encoded in one column to showrooms such as singles, doubles, twin bed units, suites, conferencerooms, and any other category of rooms in a particular hotel. The nextclassification on the card will show the type of reservation, that is,whether it is a new reservation or cancellation of an existingreservation. As will hereinafter be explained more specifically,classification maybe divided into such classifications as 6:00 PMarrival, 9:00 PM arrival, guaranteed reservation, and walk-in, andfurther may be classified as 6:00 PM no-show, 9:00 PM no-show,guaranteed no-show, and announced cancellation. Such information is readfrom column 10 of the card and applied to a classification storageregister 14. The next classifications on the card which occupyfourcolumns each show the arrival date and the final occupancy date.Such information is read from columns 12 14, 16 -18, and applied tostorageregisters l5 and 16, respectively.

The final punched classification on this particular card will indicatethe number of rooms in a given reservation or cancellation, and suchinformation is read from the card reader to a count control and feedregister 17. The month during which the occupancy will occur or duringwhich a previously made reservation is to be cancelled is applied to amonth selector unit 18 which further channels this information to thearrival date and final occupancy date storage registers and 16,respectively.

The month selector further provides a signal to a month displayindicator 19 which will display the months being utilized in a system.As will hereinafter be more fully explained, the particular unitdisclosed is a 62-day or 2-month system.

The information stored in the arrival date register and the finaloccupancy date register is applied in an occupancy days selector 20together with information in the classification register to provide anultimate indication of whether room units are to be subtracted frominventory as by additional reservations or added to inventory by reasonsof cancellation. This information is applied to a visual register andindicating portion of the system identified at 21.

The inventory of available rooms of each category is preferablydisplayed on a console or display register board 23 as shown in FIG. 3.This display board is made in six sections, 23a 23f, and will show foreach of 62 days the number of available rooms in each category. Forexample, the number of available single SGL rooms is shown in the toprow, the number of double DBL rooms, twin TW bedroom rooms, suites STE,conference CON rooms and other special SPE rooms is shown in succeedingrows. For each category of rooms for each of the 62 days there is anumerical display register 24 which is preferably in the form of anumerical counter as hereinafter more fully explained. The display boardis shown as physically arranged in six sections of 10 or 1 1 days each.This is merely for purposes of symmetry of appearance and to facilitatedisclosure as will hereinafter be made apparent.

Below each column of room categories is a day of the month numbered l-3land on each section of the console are indicator lights 25 for sixdifferent months. The odd-numbered months, January, March, May, July,September and November are available to be shown on the upper displaysections 23a, 23b, 23c, and the even-numbered months, February, April,June, August, October and December are available to be shown on thelower console sections. It will be understood that at any given time,only one of the month indicators on each console section will beilluminated.

Briefly, by way of preliminary explanation, assume that the console ofFIG. 3 is to be programmed for January 1 through February 28. All of theJanuary indicators on the upper sections 23a, 23b and 230 would beilluminated and all of the February indicators on the lower sections23d, 23c and 23f would be illuminated. Initially, each display registeror counter 24 is set to the maximum number of rooms of each category foreach day. Then the cards 11 are fed into the card reader and theinformation thereon would be utilized to decrement the counts in theregisters 24 in accordance with the reservations. In some instances, thecounters might later be incremented upon cancellations or no-shows.

As has previously been stated, the disclosed system is arranged for amaximum of 62 days or 2 months. Therefore, on January 1 I all registersin the upper left section 23a would be reset to the maximum number ofrooms available in each category, and the month of March would beselected for display thereon. Similarly, on January 22, all registers inthe upper middle console section would be reset to the maximum number ofrooms in each category so that these sections could then accept furtherreservations, cancellations and other information, and the month ofMarch would be selected for display thereon. In this way, the consolesections are preferably divided into 10- or 1 l-day sections to obtainmaximum utilization of the equipment. However, other divisions of amonth or months. This is feasible in a 2-month system inasmuch as by thesymmetry thereof only the odd months will appear on the top sections andonly the even months will appear on the bottom sections. If a 3-monthsystem were involved, each display section would then only have to showevery 4th month.

A console of the type disclosed in FIG. 3 allows an immediate visualinspection of the number of units or rooms in each category availableduring any day of a 2-month period. Assume that the reservation clerkreceives a telephone call or a letter requesting reservations for agiven period of time during the next month. The reservation clerk merelyinspects the availability of room categories for the period of timedesired, determines that such are available, then punches the necessaryinformation on a card 11 and places the card in the card reader. Thiswill cause a decrementing of the registers forthe reserved days in theproper room category. Alternatively, in smaller systems the informationmay be manually read in to the system by setting preselected switches,as will hereinafter be made apparent.

A series of indicator lamps, not shown in FIG. 3, below the selectedrooms on the reserved dates will be illuminated to allow the reservationclerk a visual check against the requested reservation to determine thatno error has been made during the card punching and reading operation.When this check has been made such indicator lamps may be extinguished,as hereinafter described.

Reference is now made to the information read-in logic or card reader10. The card reader generally comprises a Standard Register Company CardReader Type 171 l, which may be further modified as disclosed in FIG. 4to handle the necessary control power. The punch cards 11 are insertedinto card reader 10 and the perforations in each column thereon' read bya conventional star wheel contact (not shown) which sequentially readsthe perforations within each column on the card and a commutator switch(not shown) which reads the column on the card. When a perforationoccurs in one of the columns, a source of power (not shown) is connectedto a contact SO -S9. This will read a number in a given column. At thesame time the card is being advanced column-by-column to the card readerand a commutator switch contact C9 C23 will have a source of powerconnected thereto as each column is read. The contacts C9 C23 when madeindicate a particular column which is being read. In FIG. 4 thepertinent portions of the card reader 10 are shown and comprise aplurality of contacts which are made when a perforation in a columnoccurs. When one of contacts S0 S9 is connected to a source of power anassociated relay SRO SR9 is energized which picks up its controlledcontacts to connect a positive voltage to associated terminals SOA S9A.

At the same time, as the columns are read by the card reader, contactsC9 C23 may be connected to a source of negative potential to selectivelyenergize relays CR9 CR23 which will cause the selected relays to pick uptheir controlled contacts C9A C23A to a source of negative potential orground.

In the various drawings, electrically common contacts, terminals, andlines bear the same reference characters. In describing the variouslogic elements of a system embodying the invention, relays which operatebetween energized and deenergized states are set forth to facilitatedisclosure. However, it is to be understood that the various circuitsand networks may be composed of relays, vacuum tubes, semi-conductordevices or any other elements operable between two states or conditions.

As will be hereinafter more fully explained, the combination of anenergized S contact and a C contact will identify the location of aperforation on the card 11 and will convey the in telligence on the cardto a predetermined portion of the system.

The manner in which a particular room category is read will be apparentfrom reference to FIGS. 4 and 5. FIG. 5 illustrates a plurality ofmemory devices, namely, six in number, which are selected and set to anindicative state through information read from the card 11. Reference toFIG. will show that the room category is shown on column nine of thecard. As illustrated in FIG. 5 there are six room categories and amemory device in the form of a relay RC1 6 for each room category. Eachmemory device RC includes a relay coil having selflatching contacts anda pair of signal contacts. When one of the relays is energized it willpick up all of its contacts. The relay will be latched in and the signalcontacts are all connected to line 33 or 34 having positive voltagethereon. The contacts or terminals which read the room category areidentified SlA -S6A and the individual memory relays are connectedbetween one of these terminals and a common line 26 which is connectedat its other end to terminal C9A of FIG. 4; Thus, when column nine ofcard 11 is read and a perforation appears in any of positions S1 S6 aparticular category of room is called for. One of relays RC1 RC6corresponding to such room category is energized and its correspondingsignal contacts RClI RC6I, RClD RC6D closes to indicate that aparticular category of room has been called for by the card 11.

In FIGS. 4 and 5 it will be understood that each of the relays andmemories are identical in construction and those represented in blockdiagram are the same as those shown in schematic. In FIG. 5 the relaysare self-latching and serve as memory units while those shown in FIG. 4are not self-latching and intended only to give an instantaneous signalto one of terminals SlA 86A and C9A C23A.

The classification register 14 is exemplified in FIG. 6. Suchclassification register comprises a plurality of memory devices whichagain may be in the form of relays 32 and 33 which are energized throughcontacts SlA SSA by the card reader sensing perforations in column ofcard 11. The coils of the relays 32 and 33 are adapted to be energizedby completion of a circuit through one of contacts SlA SSA and contactCIOA indicating information in column 10 of the card. In FIG. 6 only onememory unit is indicated in schematic form and the remainder areindicated in block form. Each memory unit has a particular significanceand is so labeled. For example, the first column of memory units 32indicates reservations for 6:00 PM arrival, 9:00 PM arrival, guaranteedreservation, or walk-in customer. The memory units 33 in the secondcolumn each indicate a no-show or a cancellation. Hence, the memoryunits 32 in the first column, when energized, are utilized to decrementthe available rooms, while the memory units 33 in the second column,when energized, are utilized to increment the number of available rooms.

The signal terminal of each of the decrementing memories 32 are appliedto a common line 34 and the signal terminals of each of the incrementingmemories 33 are connected to a common line 35.

Accordingly, a decrementing count in any classification in memories 32will apply a signal to line 34. If any of memories 33 are energizedindicating a no-show or a cancellation, an incrementing signal isapplied to line 35. The incrementing or decrementing signals, as ishereinafter explained, are applied to terminal P and signal line P1. Theincrementing or decrementing signal is then passed through the signalcontact of the energized memory to line 35 or 34. Line 35 is connectedto the lower signal terminals of each of relays RC1 RC6 and the line 34is applied to the upper signal terminal of each of memory units Thus,the output terminals RClI RC6I and RClD RC6D upon reading columns nineand 10 of card 11 will indicate a particular room category that has beenread from the card and whether a decrementing or incrementing count isto be utilized for that room category.

Briefly stated, when the circuits of FIGS. 5 and 6 are set up, a numberof pulses may be applied to terminal P indicative of a given room countwhich is read from columns 19 and 20 on card 11 and which is applied tothe network of FIGS. 5 and 6 to the selected ones of the signalterminals of the RC relays.

It may be seen that the memories exemplified in the form of relays actas coincident networks, that is, such memories are set or energized uponthe simultaneous occurrence of given conditions.

The outputs appearing on the signal terminals RCII-RC6I, RC1D-RC6D, ofthe room category register are applied to visual display countingregisters, as shown in FIGS. 3 and 7. The array of display counters 24shown in FIG. 7 represent the display on section 23b of display 23. Morespecifically, they show the displays for an 11-day period and for sixroom categories. The displays are in the form of a counter such asVeeder-Root Company, Hartford, Conn., counter Model No. X11659 which iseither incremented or decremented by a single pulse and is so arrangedthat it will not count below zero. Each of the counters 24 will have anumber of digits selected in accordance with the number of availablerooms of a given type. The counters 24 a which indicate the number ofavailable single rooms receive inputs over line CRII and CRlD from theroom category register of FIG. 5. The counters 24b which represent thenumber of available double rooms receive inputs over lines CR2! and CR2Dfrom the room category register of FIG. 5. Similarly, the rows ofcounters 24c, 24d, 24e, and 24f receive inputs from lines CR3I, CR3D;CR4], CR4D; CR5], CRSD; and CR6I, CR6D, respectively, from the roomcategory register. The counters 24 will not be operated unless a circuitis established therethrough from a CRI or CRD line to the occupancy daysselector register, which circuits indicate the days in whichreservations or cancellations are made.

Each of the display counters 24 have an indicator light 24g associatedtherewith to indicate the days and room categories which have beenselected and thus provide a visual check to the operator. Such lamps arearranged 'to be illuminated by the coincident application of a signal ona category signal line L1 L6 and occupancy day signal line DM. Each ofrelays RC1 RC6 will connect a line Ll L6, respectively, to positivevoltage when energized. Each of lines L1 L6 is connected to a series oflamps 243 (FIG. 7) for a corresponding category of rooms for each day(only one day shown for each category. Each lamp is further connected toan associated day line DM.

FIG. 8 illustrates in simple schematic form the operating mechanism ofone of the counters 24. Each counter comprises an addactuating coil 27and a subtract-actuating coil 28 which receive inputs from a RCI or RCDterminal, each of which when energized is adapted to advance or reversecounting wheels 29 having numbers serially displayed thereon adapted tobe viewed through a window port as exemplified in FIG. 7. The unitcounting wheel is arranged to operate a detent or other means 29a whenthe absolute sum in the counter decrements to zero, which will open aswitch 29b and prevent further decrementing of the counter. A circuit iscompleted through one of the coils 27 or 28 when a negative signalappears at the occupancy day selector, as will hereinafter be more fullydescribed.

The function of the arrival date register 15 together with the monthselector 18 and month indicator 19, are shown in FIG. 9. The register 15comprises a plurality of logic elements adapted to be set in a given oneof two stable conditions upon the occurrence of coincident signals, andupon such coincident signals transmit a signal therethrough. It will berecalled that the system under description is a 2-month or 62-daysystem. Accordingly, 2 month memories 50 and 51 are provided, fourdecade day memories 52 55 are provided, and IO-unit day memories for dayzero through day nine, 56 -65 are provided. With reference to FIGS. 2and 4, the information on the card 11 under the classification arrivaldate is read into the arrival date register 15 of FIG. 9 as follows: Thearrival date classification on card 11 comprises four columns. As shownin FIG. 2, these columns bear the number 0612 which indicates a 6-month,18th day arrival date. The 06 indicates the month of June which is aneven month and, accordingly, a signal is applied to terminal M32 evenmonth memory from month selector 18a. At the same time the C13 contactsindicate that this information is in column 13 and a signal is appliedto terminal Cl3a.

This will, in turn, set memory 51 which applies signals from terminalMS2' to decade day selectors 52, 53, 54 and 55. One of these memorieswill be set upon the reading of column 14 on card 11. Referring to theexample on the card, it will be seen that the arrival date falls betweenthe 10th and 19th. Therefore, when card column 14 is read a signal willbe applied to terminal C14A and simultaneously to terminal SlA whichwill set memory 53. Each of memories 52 55 is adapted to yield twooutput signals. One of the output signals is indicative of an odd monthand a day within its range, while the other signal is indicative of aneven month and the day within its range. The outputs of each of memories52 55 is marked to indicate its possible output. For example, the outputof memory 53, M110, indicates that the arrival date is in an oddoreven-numbered month and is within the 10th to 19th day span. Similarly,the output marked M210 indicates that the arrival date is in aneven-numbered month and the date falls within the 10th to 19th day span.The outputs of the memories 52 55 are indicated on the common bus linesrunning vertically in the drawing.

At this point, after reading the first three columns in theclassification arrival date on card 11, the selected ones of the monthand decade days memories have been set. In the example given, thissignal will appear on line M210. When the fourth column in the roomarrival classification of card 11 is read, terminal C A will beenergized and terminal S2A representative of the second day will also beenergized. These coincident signals to memory 58 will set memory 58 andenable it to provide a signal on its output line M212A. In effect,memory 58 when set passes the signal on line M210 to its output terminalM212A. This now signifies that the arrival date .lune 12 has been readfrom card 11 and the arrival date register 15 has read such informationfrom the card and energized an appropriate line.

It may be readily seen that in a similar manner any day of an odd oreven month may be read from the card.

Reference is now made to the month selector l8 and the even and oddmonth selectors 18a and 1812, respectively.

The month selectors have a two-fold function. One function is toindicate on each section of the display of FIG. 3 the month indicated bythat console.

A selector switch is associated with each section of the console. Theodd month selector 18b which comprises selector switches 18c, 18d and18e illuminate the month indicator lights 24 on the upper three sections23a, 23b, and 23c of the display, while the even month selector 18athrough selector switches 18f, 18g, and 18h will illuminate the monthindicators 24 on the lower three sections of the display of FIG. 3. Asshown, the selector switches 18c, 18d and 18e will illuminate theJanuary illuminers on the upper three sections of the console and theselectors 18f, 18g and 18h will illuminate the month February on thelower three sections of the console. The selectors, as shown, comprisesix position rotary switches with two sets of six terminals. The firstset of six terminals of each of selectors 18c, 18d and 18a are connectedto terminals 51A, 89A, 87A, SSA, 53A and 81A of the card reader.Connected to the movable contact of each of the selectors is the lineMSl which is, in turn, connected to memory 50. Thus, when any of the oddmonths are read from the card, line MSl will be energized and will applya signal to memory 50. When such signal coincides with the reading ofcolumn 13 on the card, memory 50 will be set or energized.

Selector 18a operates in a similar manner on contacts SOA, 88A, 86A, 82Aand SOA and when the circuits are properly selected will apply a signalat terminal MS2 to memory 51.

Assume that the system initially displays the month of January acrossthe upper sections thereof and the month of February across the lowersections thereof, and that the first 10 days of January have passed.Selector 18c will be set to March and arranged to read an input fromterminal S3A. This will then change the month indicator on the upperlefthand section 23a of the display to illuminate the indicator for themonth of March. Similarly, when the 21st day of January has passed,selector 18d will be turned to contact S3A which will allow reservationsto be read in for the March llth 21st period'and will illuminate theMarch month indicator on the middle upper section 23b. Subsequently,after each 10- or 11- day period the overall register will be updated ina left-to-right sequence as viewed in FIG. 3. Each time a section of thedisplay is updated the appropriate month indicator is illuminated.

The outputs of the memories 56 65 are each indicative of 1 day in a2-month or 62-day period. Such outputs are indicated by the prefix Mfollowed by the numeral one to indicate the odd month and the numeraltwo to indicate the even month. The last two digits of a referencecharacter indicate the day of the month and the suffix A indicates thatthis is an arrival date.

Each of the memories 50 65 may comprise self-latching relays with aplurality of signal contacts as previously described. For example, thememories 56 65 will provide a total of 62 signal contacts or terminals.Where relays are utilized as the memories the signal contacts thereofare normally open when the relay is de-energized.

The final occupancy day register 16 is identical in construction to thearrival day register 15 with the exception that the signal contactsthereof are normally closed when the relay is de-energized. Thus, when agiven final occupancy day is read from the card 11, one of the terminalsindicative of that day has no voltage thereon.

The final occupancy day register, shown in block form in FIG. 10,comprises odd and even month memories 70, 71 which receive inputs overlines M81 and M82 and an input from terminal C16A. The decade daymemories 72, 73, 74 and 75 receive inputs from contacts SOA, 81A, 82A,and 53A, respectively, and from terminal 17a when column 17 of the cardis read. The unit day memories 76 85 receive individual inputs fromterminals SOA 89A, respectively, when column 18 on the card throughterminal C18A is read. The memories 76 85 have a total of 62 outputseach indicative of one day in a 62 -day period and identify in the samemanner as the signal outputs of the arrival day register except that thesignal output terminals in the final day occupancy register 15 bear thesuffix F.

The final occupancy date register 16 is identical in construction to thearrival date register 15 except for slight differences in operation. Therelay signal contacts provide a positive potential signal whenenergized, while the relay contacts in memories 56 65 provide a negativepolarity signal when energized. The relay contacts in the arrival dateregister are normally open when their associated relays arede-energized. In the final occupancy date register the relay contactsare normally closed when the associated memory relays are de-energized.

The occupancy date selector 20 is set forth in FIG. 11, partly inschematic and partly in block form and comprises 62 memory units ofwhich 34 are shown.

The relays shown are D231 D202, each memory relay being representativeof an odd or even month and the day in that month. Accordingly, it willbe apparent that the relay D131 represents the odd month and the 31stday thereof.

The coil of each of the relays receives at either end thereof signalsfrom the arrival date register 15 and the final occupancy date register16 corresponding to the date of the month represented by the energizedsignal terminal of that register. For example, the coil of relay D101receives at its upper terminal a signal from terminal M101F (FIG. 10) atits lower terminal a signal at terminal M101A of the arrival dateregister 15 (FIG. 8).

Assume that a registration or cancellation is to be made commencing onthe 31st day of an even month through the third day of the next month,relay D231 would receive a negative signal at terminal M231A. At thispoint it will be recalled that on the unit day memories of the finaloccupancy register the signal contacts are normally closed and apositive potential applied thereto. Therefore, the coil of relay D231will become energized and close its controlled contact. This willconnect the lower terminal of the coil of relay D101 to negative busline 80. Relay D101 will become energized and close its control contactto connect the lower terminal of the coil of relay D102 to line 80. Thecoil of relay D012 will then become energized and close its controlledcontact to connect the lower terminal of the coil of relay D103 to line80. However, in the final occupancy date register the contact toterminal M1031 has been opened when relay memory 79 is energized.Accordingly, the coil of relay D103 is not energized.

At this time, the lines DM231, DM101, DM102 and DM103 will be connectedthrough the closed relay contacts to the negative bus line 80. This willsupply a negative control potential to the display and indicatorregisters 24 shown in FIGS. 7 and 8. Accordingly, the selected countingregisters 24 are now set up for incrementing or decrementing by apredetermined number of rooms as will be read from columns 19 and '20 ofcard 11.

In FIG. 11 only 34 of the 62 days are represented by the memories D231-D202. It will be understood, however, that in the system describedthere will be 29 additional memories serially arranged in a loop. Thearrival date information and final occupancy date information may beapplied to any position as desired on the day selector register. Thisregister will automatically operate to produce a circuit for each daywhich occupancy is reserved or, alternatively, cancelled. FIG. 11further indicates the importance of the final occupancy date signal. Ifonly an arrival date was read into the system without a final occupancydate, it will be apparent that the whole serial register would be set upinasmuch as no signal would be removed from the upper terminals of anyof the day relays. This feature of construction, however, is utilizedwhen initially setting the system for the total occupancy period.

When the appropriate display counters, as exemplified in FIG. 8, havebeen selected by energizing one or more of the DM lines and theappropriate CR1 or CRD line, the display counters are then enabled toreceive either incrementing or decrementing pulse counts where eachpulse count is indicative of a room to be reserved or a previousreservation cancelled.

The count control and feed register 17 of FIG. 1 is more specificallyset forth in FIGS. 12 and 13. The number, of units to be reserved orcancelled are read into and stored in number register 90, FIG 12. Suchnumber in tens is read into relay memories NDO-9 and in units in relaymemories NUO-9. The number in tens is read in when column 19 of card 11is read through contact C19A by the individual inputs SOA S9A.Similarly, the unit numbers are read in from card column 20 at terminalC20A and through individual inputs SOA S9A. It will be apparent that ifthe number of rooms to be reserved is, say, 11, relay memories NDI andNUl will be energized and latched in. The signal contacts of theserelays will be connected to common bus lines 91 and 92 which are, inturn, connected to lines 93 and 94, respectively, for purposeshereinafter set forth. The signal contacts of each pair of associatedrelays is further connected to contacts T16, T18, T20, T22, T24, T26,T28, T30, T32 and T34 in inverse order to the storage number representedby the memory relays. Between each set of these contacts is auni-directional conducting device 84.

As will hereinafter be more fully explained, positive-going pulses aresequentially applied to each of contacts T16 T34 to read the complementof the number stored in number register 90. Reference is now made to thecount control network shown in FIG. 13.

The network of FIG. 13 includes a sequence and time base generator inthe form of a stepping switch 96 having a contact arm 97 whichsequentially steps along contacts T1 T40 which also provide timingmarkers. It will be understood that the number of contacts that areutilized is a function of the marker times desired. The contact arm 97in making contact with the terminals Tl T40 as the arm 97 is steppedprovides a series of marker or timing pulse signals. It is to beunderstood that such marker or timing signals may be derived from otherequipment such as an electronic marker or time base generator.

The network of FIG. 13 further includes a buffer or temporary storagecounting register 99. In the embodiment of the infurther include aswitch 103 (only shown on the units counter) which closes as thecounting wheel moves from zero to nine to simulate a carry, and a switch104 which opens when the count is zero. When switch 103 closesindicating a borrow, a line 105 is connected directly to counter 101 toeffect such borrowing action.

To summarize, the temporary storage register 99 is utilized totemporarily store the number of rooms read from number register 90 andthereafter to monitor the pulses derived from a pulse generator 106 andapplied to selected ones of display register 24.

The network of FIG. 13 utilizes seven bi-stable devices in the form ofrelays 107-113. Relay-107 is energized when all previous data has beenread into the system, and the system is ready to increment or decrementthe counting registers 24 by the number in card columns nineteen andtwenty. Relay 107 is enabled from terminal C21A and is energized throughtime T40.

Relay 108 controls the application of pulses from pulse generator 106 tov a stepping switch actuator 114 which operates the arm 97 of timingswitch 96, and also controls the application of pulse counts toclassification register 14, FIG. 6. Relay 108 is energized at time T38.

Relay 109 also acts to control the application of pulses from pulsegenerator 106 to classification register 14, FIG. 6, and to decrement tozero the number of units read into storage register 99 from numberregister 90. Relay 109 is also energized at time T38.

Relay 110 acts to clear storage register 99 during times T2 T14. It isenergized at these times. When energized it completes a circuit throughstorage register 99 to the negative voltage line, and thus acts as apower control during the clearing time.

Relay 111 functions as a power control for storage register 99commencing at time T15 when a new number is read in from number register90. When energized it unlatches relay 1 l0.

Relay 112 at time T36 provides a signal to the card reader 10 to signifythat a cycle of operation is complete and print a validating legend oncard 11 in block 11a.

Relay 113 at time T37 opens the positive voltage supply to relay 107 toshut down the counting network.

When card column 21 is read, terminal C21A is energized and an enablingsignal is applied to a relay 107.

When an energizing signal is applied to relay 107 it applies positivevoltage over line 115 from positive bus line 115a to the movable contactarm 97 on the time sequence generator 96. Simultaneously, it enablespulse generator 106 which commences to generate positive-going pulses.Such pulses are applied through the contacts of relay 108 and lines 116and 117 to stepping switch actuator 114 which commences to index arm 97in timed steps about the contacts Tl T40. When contact or time T2 isreached, an energizing signal is applied to relay 110 over line 118 andrelay 110 is set or latched in. As arm 97 moves to contact T3 andsubsequently moves through T14, each movement of the contact on one ofthe terminals T3 T14 produces a positive-going pulse which is appliedover line 119 through relay 110 and lines 120 and 121 to counters 100and 101, respectively, in parallel. At this time coils of both ofcounters 100 and 101 are returned to negative voltage over line 122through relay 110. Accordingly, as arm 97 indexes from -Tl4 it willgenerate a total of l l positive-going pulses which are utilized todecrement the counters to zero. These pulses are applied to the countersin parallel. At any time during the sequence when the counters reachzero, the switches 104 open.

The counters 100 and 101 are inherently designed not to decrement pastzero in a positive direction. That is, they will move from zero to nine,but not from zero to one.

When arm 97 makes contact with terminal T an energizing signal isapplied over line 123 to relay 111. When energized memory 110 latches inand accomplishes two functions. It opens line 124 to de-energize memory109 and it further connects line 125 to negative voltage.

At this time, the temporary storage register has been decremented tozero, relays 107 and 111 are energized or set and relays 108, 109, 110,112 and 113 are de-energized. Relay 110 is energized only from time T2through T14 at which time any number in register 99 is decremented tozero. At this time, arm 97 will sequentially make contact with terminalsT16 T34 which correspond to the terminals T16 T34 in the number registerof FIG. 12. As arm 97 moves past each of terminals T14 T34 a pulse isgenerated which is sequentially applied to the terminals T16 T34. Suchpulses may be applied to lines 93 and 94 through the signal contact ofthe energized ones of the ND and NU relays, FIG. 12. In the examplepreviously given, assume that relays NDl and NUl are energized, as arm97 steps from T16 to T32.

As arm 97 sweeps through contact T16 T32, nine pulses will be producedwhich are applied to line 127. Line 127 includes the uni-directionalconducting devices as well as the T16 T34 terminals. The pulses appliedto the terminals T16 T34 pass along line 127 to seek the signalterminals of the relays which are closed and, hence, to lines 91 and/or92 and then lines 93 and 94. Lines 93 and 94 are connected to lines 120and 121 through relay 110, hence, nine decrementing pulses are appliedsimultaneously to each of counters 100 and 101. This will decrement thecounters to show a total of eleven therein. After the arm 97 moves pastcontact T32, the diode 84 between terminals T32 and T34 prevents anyfurther application of pulse counts to lines 93 and 94.

The temporary storage register 99 is now set with the number stored inthe room number register of FIG. 12.

When terminal T is reached, an optional checking feature may beemployed. At this time the system is prepared to incrementor decrementthe selected registers 24. Provision is made for the operator to delaythis action until the indicator lamps 24a under the selected registers24 are checked. At T35, a

relay 130 is energized over line 131 and opens its contact in line 117to interrupt pulses to actuator 114 and halt advance of arm 97. If thelamps 24a indicate that the day selection is accurate, the operatorcloses switch 132 to reapply pulses to actuator 114. At time T36 anenabling or energizing signal is applied over line 133 to relay 112.When this occurs, relay 112 closes its contact and signals card reader12 which prints a validating legend in box 11a on card 11. Copies of thevalidated card may then be utilized as hereinafter described.

At time T38, arm 97 energizes line 134, and relay 108. The lower contactof relay 108 connects the coil of relay 109 to lines 122 and 125 and,hence, negative voltage to complete a circuit therethrough. When relay108 is energized it opens the circuit between lines 116 and 117 andinhibits actuator 114, thus halting arm 97. Line 116 now connects pulsesfrom generator 106 to the closed contacts of relay 109, and such pulsesare simultaneously applied to lines 135 and 136. Line 136 leads toterminal P in the classification register (FIG 6). Line 135 is connectedto line 121 which applies the pulses to unit counter 99. Assuming thenumber in storage is 11, at the application of the second pulse, switch103 closes and positive voltage is applied to counter 101 over line 137.This decrements the decade counter to zero and switch 104 in counter 101opens. After nine more pulses, counter 100 is decremented to zero andits switch 104 opens. This opens the circuit through the coil of relay1009 by disconnecting line 138 from lines 122 and 125. The contacts ofrelay 109 return to their normal position, the circuit to line 136 isbroken, and application of pulses to lines 135 and 136 is interrupted.Simultaneously, a circuit from line 116 through lines 139 and 140 isestablished to line 117 and actuator 114 is again rendered operative.

As arm 97 advances to T40, relay 113 is energized to open its contactand remove voltage from line and tie-energize relay 107. The network ofFIG. 13 is now disabled and awaits a new cycle of operation when anothercard is read.

In the described operation 11 pulses were transmitted to terminal P inclassification register 14, FIG. 6, which are in turn applied to one oflines 34 or 35. Lines 34 or 35 will convey the pulses to the selectedRC1 or RCD lines in room category register 13, FIG. 5, and hence to theselected RC lines in FIG. 7. The pulses will be applied to the selectedday counter registers 24 having energized DM lines, and the counterregisters will be appropriately indexed.

The invention has been disclosed within a system in which information isread in from a prepared record medium. It will be apparent that theread-in of infonnation to the system could be accomplished manually byappropriately substituting push-button or other type switches to setinformation in the various registers. For example, the classificationregister could be reduced to two relays for reservation and cancellationwhere no permanent record is desired and each of such relays could beactuated by a manually operated switch. In all registers and controls,the bi-stable devices may easily be operated by manually operatedswitches rather than from the card reader 12.

However, the use of the cards 11 provide an added benefit in that theymay be stored and then utilized in a data processing system to derive astatistical analysis of the establishments of business over a period oftime. The cards 11 may be in duplicate or in triplicate. The cardsbearing the reservation validation may be mailed to the customer toverify the reservation, a second card may be held for checkout purposesand a third card utilized for a permanent record.

When the illustrated system is initially set up for operation for aperiod including a predetermined number of units of time, all of thecounters 24 will be at zero or may be set to zero. Then a card isprepared for each room category for each unit of time and fed into thesystem as incrementing counts.

This will set all of the counters 24 to the total units in inventory oravailable. Thereafter, the cards which have the reservation data thereonare fed into the system and the appropriate counters 24 are decrementedto show the remaining available units during any unit of time.

The invention has been disclosed in a hotel or motel reservation system.However, it will be apparent that it will have many other utilizationsto account for items of inventory which are used over units of time.Such uses, for example, might be in the leasing of equipment, such asautomobiles, use of hospital rooms, or any other system which requiresaccounting of categories of items, number of it items and times of useof such items or stores of materials.

It may thus be seen that the objects of the invention set forth as wellas those made apparent from the preceding description are efficientlyattained. While a preferred embodiment of the invention has been setforth for purposes of disclosures other embodiments and modifications tothe disclosed embodiment of the invention which do not depart from thespirit and scope of the invention may occur to those skilled in the art.Accordingly, the appended claims are intended to cover all embodimentsof the invention as well as modifications to the disclosed embodimentwhich do not depart from the spirit and scope thereof.

What is claimed is:

1. A system for continuously visually displaying the status of aninventory of items over a period of time defined by a plurality of unitsof time, comprising a plurality of numerical display devices eachcorresponding to a unit of time, said devices being arranged to displaythe availability of a number of items for a unit of time, said devicesbeing arranged in sequential order of units of time to display theavailability of the items over the defined time period, means forselecting a number of items and the units of time said selected numberof items are to be utilized, and means responsive to said selectionmeans for decrementing the numerical information in the display devicescorresponding to the selected units of time by the selected number ofitems.

2. The system of claim 1 wherein said display devices corresponding tounits of time are divided into groups of units of 7 time, and means forresetting the display devices of each group to indicate an additionalgroup of units of time.

3. The system of claim 2 wherein said units of time are days and saidgroups comprise a plurality of successive days.

4. The system of claim 3 wherein each succeeding three groups of daystotal 3 l and no group is greater than l 1 days.

5. The system of claim 1 further including means for displaying aplurality of categories of items for said predetermined units of time,and said means for selecting includes category selection means.

6. The system of claim 1 wherein the items are rooms and the units oftime are days.

7. A system for displaying the availability of a plurality of rooms fora predetermined number of days, comprising a plurality of countingregisters sequentially displaying the available number of rooms for eachday, means for selecting the days a number of rooms are to be reserved,and means responsive to said selection means for decrementing theregisters corresponding to the selected days by the selected number ofrooms.

8. The system of claim 7 wherein said day registers are classified intogroups, a plurality of month indicators for each group, means forselecting a month of operation for each group, and means for energizingthe indicator of the month selected.

9. The system of claim 7 wherein the number of days displayed areselected to display N months, said day registers being classified intogroups where a given plurality of groups add to at least 1 month, eachof said groups having 12/N month indicators associated therewith wheresaid month indicators are adapted to display each l2/Nth month.

10. The system of claim 9 further including a month selector for eachgroup of days, and means responsive to said month selector forenergizing the indicator on each group for the selected month.

11. The system of claim 9 further including means for selecting aparticular l2/Nth month for operation, and means responsive to selectionmeans to enable said group to accept information only in the monthselected.

12. A system for visually displaying a number of stores in inventory foreach of a predetermined number of serial units of time, comprising aplurality of counter means each corresponding to a unit of time, saidcounter means being arranged to visually display the number of availablestores for each unit of time, means for selecting a predetermined numberof stores for use between two units of time, and means responsive toselection of said two units of time for changing the number displayed bysaid counters between said two units I the selected number of stores, abuffer register, means for setting the number in said number register insaid buffer register, means providing a train of pulses, means forapplying the ulses of said train to one or more counter means and tosaid uffer register to decrement the number in said buffer register, andmeans for interrupting application of the pulses to said one or morecounter means when the number in said bufier register reaches zero.

15. A system for continuously displaying a number of items available foruse in each of one or more categories for a predetermined number ofunits of time comprising record means for visually showing the number ofitems, category of items, initial unit time of use, and final unit timeof use, storage means for storing the number of items, category ofitems, initial unit time of use and final unit time of use, means forreading said record means and storing the information thereon in saidstorage means, numerical display means for displaying the number of eachitem available for use in each category for each unit of time, and meansresponsive to said storage means, for changing the number in each ofsaid numerical display means in a category between said initial unittime of use and said final unit time of use by the number of items onsaid record means.

16. The system of claim 15 further including a buffer register, meansfor setting the number of items in said storage means in said bufferregister, means providing a train of pulses, means for applying thepulses of said train to said numerical display means between saidinitial unit time and said final unit time and to said buffer registerto decrement the number in said buffer register, and means forinterrupting application of the pulses to said numerical display meanswhen the number in said buffer register reaches aero.

17. The system of claim 15 where the units of time are days, saidnumerical display means being arranged in groups of days where aplurality of groups of days total at least 31 days, l2/N monthindicators associated with each group of days, where N is the number ofmonths displayed by said system, and means for energizing a monthindicator for each group of days in accordance with the month in whichsaid each group of days resides.

18. A system for continuously visually displaying a number of itemsavailable for use in each of one or more categories for each of apredetermined number of units of time comprising a plurality of countermeans each adapted to display the number of items available for a unitof time, means for selecting and storing the number of items, categoryof items, initial unit time of use and final unit time of use, and meansresponsive to said storage means for changing the number in each counterin a category between said initial unit time of use and said final unittime of use by the number of items selected and stored.

UNKKED STATES PATENT UFFICE emm rmm or cosmmrow 3,656,113 Datea April11, 1972 Patent: No.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 5, line 1-, after "FIG." insert 2 Column 5, line ll, after"identified" insert as Column 10, line 71, after "from" insert T3 Column11, line 17, after "Tl i" insert a dash. 'Column 11, line 69,delete"1009" and substitute therefor 109 r Signed and sealed this 26th day ofDecember 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT Q'OTTSCHl-ELK Attesting Officercommlssloner o1 Patents

1. A system for continuously visually displaying the status of aninventory of items over a period of time defined by a plurality of unitsof time, comprising a plurality of numerical display devices eachcorresponding to a unit of time, said devices being arranged to displaythe availability of a number of items for a unit of time, said devicesbeing arranged in sequential order of units of time to display theavailability of the items over the defined time period, means forselecting a number of items and the units of time said selected numberof items are to be utilized, and means responsive to said selectionmeans for decrementing the numerical information in the display devicescorresponding to the selected units of time by the selected number ofitems.
 2. The system of claim 1 wherein said display devicescorresponding to units of time are divided into groups of units of time,and means for resetting the display devices of each group to indicate anadditional group of units of time.
 3. The system of claim 2 wherein saidunits of time are days and said groups comprise a plurality ofsuccessive days.
 4. The system of claim 3 wherein each succeeding threegroups of days total 31 and no group is greater than 11 days.
 5. Thesystem of claim 1 further including means for displaying a plurality ofcategories of items for said predetermined units of time, and said meansfor selecting includes category selection means.
 6. The system of claim1 wherein the items are rooms and the units of time are days.
 7. Asystem for displaying the availability of a plurality of rooms for apredetermined number of days, comprising a plurality of countingregisters sequentially displaying the available number of rooms for eachday, means for selecting the days a number of rooms are to be reserved,and means responsive to said selection means for decrementing theregisters corresponding to the selected days by the selected number ofrooms.
 8. The system of claim 7 wherein said day registers areclassified into groups, a plurality of month indicators for each group,means for selecting a month of operation for each group, and means forenergizing the indicator of the month selected.
 9. The system of claim 7wherein the number of days displayed are selected to display N months,said day registers being classified into groups where a given pluralityof groups add to at least 1 month, each of said groups having 12/N monthindicators associated therewith where said month indicators are adaptedto display each 12/Nth month.
 10. The system of claim 9 furtherincluding a month selector for each group of days, and means responsiveto said month selector for energizing the indicator on each group forthe selected month.
 11. The system of claim 9 further including meansfor selecting a particular 12/Nth month for operation, and meansresponsive to selection means to enable said group to accept informationonly in the month selected.
 12. A system for visually displaying anumber of stores in inventory for each of a predetermined number ofserial units of time, comprising a plurality of counter means eachcorresponding to a unit of time, said counter means being arranged tovisually display the number of available stores for each unit of time,means for selecting a predetermined number of stores for use between twounits of time, and means responsive to selection of said two units oftime for changing the number displayed by said counters between said twounits of time by the selected predetermined number.
 13. The system ofclaim 12 wherein said counter means are responsive to pulses to changethe number displayed therein, and further comprising a number registerarranged to receive and store the number of selected stores, a temporarynumber storage register, means providing a sequence of timing signals,means responsive to a first number of said timing signals for clearingsaid temporary storage register, means responsive to a succeeding secondnumber of said timing signals for setting the number in said numberregister in said temporary storage register, means for generating aseries of pulses, means responsive to setting of said temporary storageregister for applying pulses of the series to selected counter means andutilizing the pulses to decrement the number in said temporary storageregister, and means for interrupting application of the pulses to saidcounter means when the number in said temporary storage register reacheszero.
 14. The system of claim 12 wherein said counter means areresponsive to pulses to change the number displayed therein and furthercomprising a number register for statically storing the selected numberof stores, a buffer register, means for setting the number in saidnumber register in said buffer register, means providing a train ofpulses, means for applying the pulses of said train to one or morecounter means and to said buffer register to decrement the number insaid buffer register, and means for interrupting application of thepulses to said one or more counter means when the number in said bufferregister reaches zero.
 15. A system for continuously displaying a numberof items available for use in each of one or more categories for apredetermined number of units of time comprising record means forvisually showing the number of items, category of items, initial unittime of use, and final unit time of use, storage means for storing thenumber of items, category of items, initial unit time of use and finalunit time of use, means for reading said record means and storing theinformation thereon in said storage means, numerical display means fordisplaying the number of each item available for use in each categoryfor each unit of time, and means responsive to said storage means, forchanging the number in each of said numerical display means in acategory between said initial unit time of use and said final unit timeof use by the number of items on said record means.
 16. The system ofclaim 15 further including a buffer register, means for setting thenumber of items in said storage means in said buffer register, meansproviding a train of pulses, means for applying the pulses of said trainto said numerical display means between said initial unit time and saidfinal unit time and to said buffer register to decrement the number insaid buffer register, and means for interrupting application of thepulses to said numerical display means when the number in said bufferregister reaches zero.
 17. The system of claim 15 where the units oftime are days, said numerical display means being arranged in groups ofdays where a plurality of groups of days total at least 31 days, 12/Nmonth indicators associated with each group of days, where N is thenumber of months displayed by said system, and means for energizing amonth indicator for each group of days in accordance with the month inwhich said each group of days resides.
 18. A system for continuouslyvisually displaying a number of items available for use in each of oneor more categories for each of a predetermined number of units of timecomprising a plurality of counter means each adapted to display thenumber of items available for a unit of time, means for selecting andstoring the number of itemS, category of items, initial unit time of useand final unit time of use, and means responsive to said storage meansfor changing the number in each counter in a category between saidinitial unit time of use and said final unit time of use by the numberof items selected and stored.